


Apologies.

by Sonamyluffer101



Category: Underfell - Fandom, Undertale (Video Game)
Genre: Anxiety, Biting, Cheating, Edgelord, Edgy, F/M, Fluff and Angst, Leaving a cheater, Makeup Sex, Obsession, Panic Attacks, Possessive Sans, Reader is weak, Reader-Insert, Sexy Times, Sexy times in first chapter, Soulmates, Underfell, Underfell Sans, forgiving a cheater, insecure reader, reader could be frisk, reader has anxiety, undertale - Freeform
Language: English
Status: Completed
Published: 2017-04-20
Updated: 2017-04-21
Packaged: 2018-10-21 09:00:10
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 3,324
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10682040
Author URL: https://archiveofourown.org/users/Sonamyluffer101/pseuds/Sonamyluffer101
Summary: You come home and hear moaning and grunting coming from the inside of your bedroom.Your boyfriend is sleeping with another girl.Three different endings, all same story.





	1. Neutral.

**Author's Note:**

> I should be working on I can protect you. Why do I keep doing this. 
> 
> Poor reader.

**Summary for the Chapter:**

> READER HAS ANXIETY.
> 
> READER IS WEAK.
> 
> Poor baby.

Standing outside of your shared bedroom door, you hear moaning and grunting coming from the inside.

 

This wouldn’t be unusual if you had only heard Sans, but you also heard a more feminine voice. 

 

 …

 

 _Fuck. No_. This was **_NOT_** happening. 

 

…

 

You open the door swiftly and watch as your boyfriend quickly untangles himself from some skanky looking girl that you’d never seen before. He stared at you for a few seconds, disbelief on his face.

 

“Princess, I-“ he starts, but you cut him off with a dismissive wave of your hand.

 

“Get out.” You say to the girl, your voice stern but wavering slightly. Thankfully, she didn’t argue. She quickly got up and put her clothes back on, and before she passed you she said “I-I’m so sorry. I didn’t know.” With a look of pity in her eyes, and she left quickly.

 

“Kitten…”

 

 

You look over at Sans, he was staring at you with a stern expression. You didn’t say anything, you just walked over to the closet and pulled out a bag. 

 

You start to stuff your clothes into it, carelessly as you wanted to get out of there before you started to cry.

 

“Oh, fucking hell.” You hear him quietly murmur.

 

He stood up and pulled his pants back on “Stop it, you aint leaving me.” He said as he grabbed your arm, but you quickly snatched it away.

 

“Don't _fucking_ touch me!” you shout at him, the tears you were holding back finally coming out. “Oh fuck,” he said softly under his breathe, and his eyes went soft. “Don't cry, no, no, no please don’t.” he held your face in his hands and you let the tears fall freely. You pulled yourself away from his gentle touch reluctantly, and made your way over to the dresser, shoving more miscellaneous items into your bag. 

 

“Stop!” he commanded once again, grabbing your bag and pulling it away from you successfully. 

 

“Fuck you, give it back! I’m done, _we’re_ done! You’re an asshole!” he used his magic and made you stay still. You started sobbing uncontrollably. This wasn't fair.

 

How could he do this to you? He said he loved you, and he fucking cheated on you!?

 

“Fuck. I’m sorry baby.” He said under his breathe and held you against his chest. You wanted to move away but his magic was to strong. “I hate you! _How could you do this to me!_?” you scream against his chest. He just held you tighter and rubbed your back. “I’m sorry baby girl.” You felt him kiss the top of your head, and you wanted so badly to just punch him and run.

 

He laid you down onto the bed, still holding you still with his magic and hovered above you. You were still crying, now feeling more insecure than ever. You weren’t good enough to keep him from cheating. “Deep breathes. It’s okay. Relax and lets talk.” He said softly, using the same voice he did whenever you had a panic attack. Were you having a panic attack? It felt like it.

 

You finally managed to get your sobs to turn into a quiet whining. He sighed softly and rubbed your side, kissing your forehead. “Don’t.” you said weakly, but he ignored you. 

 

“I love you.” He said softly, his mouth suddenly against your neck.

 

“ **Fuck. You.** ” You spitefully manage to spit out.

 

He chuckled. “As you wish.”

 

…

 

Fuck. 

 

…

 

He starts to rub his hand from your side down to your shorts, sneaking his hand inside. You whimper slightly, which cause him to let out a chuckle. “I-I said don’t touch me!” you scream at him, trying your best to get out of his magic grip, but to no avail.

 

“I love you.” He said once again. You felt the tears start to come back at a stronger pace. He was making it worse.

 

…

 

“W-why?” you squeak out desperately. He froze above you, taken aback. He looked at you, a type of tenderness in his eyes. “What d-did I _do?”_ you ask him, desperately trying to find an answer. You were starting to sob with hiccups in between. You felt so broken. So betrayed. You always did whatever he asked of you. You loved him and treated him as best as you could. He never complained and never gave any sign he was unhappy, so what the fuck did you do?

 

“Shit baby girl… you didn’t do anything wrong. Shh.” He spoke softly, pressing a gentle kiss against your forehead. 

 

He released your hands and you desperately clung to him, your anxiety going everywhere. At this point, you just wanted him to hold you. You wanted him to tell you how beautiful you were, and that you were his world. Only now you knew it was all lies. 

 

You try to push him off of you, but he sighs and becomes dead weight. “Get off.” You say weakly, pushing at him.

 

“I can't. I’ve fallen for ya.” He said with a smile so big it made your heart melt. You couldn’t help but laugh at his stupid joke, and you hated yourself for it. But your laughter turned to sobs and he looked so sad and worried.

 

“I’m sorry.” You say softly. He looks so shocked and confused. 

 

“Fuck you mean _you're_ sorry?” he asked gently, cupping your face in his hands.

 

“I-If I was better you wouldn’t have wanted to cheat.” You manage to stutter out, moving your face away from his hand.

 

He looked broken. Confused. Angry. Shocked. “No. This _NOT_ your fault. Not at all. I was being selfish, and I was being stupid. I am so, so fucking sorry, this will _not_ happen again I fucking promise you that.” He looked into your eyes as he spoke, and you felt small. 

 

“You're right. It won’t happen again.” You say softly. He smiles a little. “Because we're done.” His smile instantly drops.

 

You stare up at him, waiting for him to get off, but he wouldn’t. You start to struggle and he _fucking growls_  at you. “Let go!” you squeak out desperately.

 

“No. You’re ** _m i n e._**  You aren’t leaving, I won’t _fucking let you_.” He used his magic once again, and you were really starting to get pissed.

 

“Sans, I can’t be a fucking idiot anymore! You just fucking cheated on me! You can’t keep me here against my will!” you shout, trying so hard to kick him.  He hid his face in your shoulder and kissed it.

 

“I _need_ you. You're _mine_. You're **not** leaving me.” His voice was deep and possessive. You were starting to get antsy, because whenever he got like this it ended in hard sex and gentle aftercare. You weren’t in the mood for either with him.

 

You let out an uneven and shaky breathe, and softly say “Okay. I won’t leave. But I don’t wanna see you right now.” 

 

 **“To fucking bad.”** He was starting to shake and you could tell he was about to have a panic attack. His voice was wavering and slightly broke at the end. Good. It seems the thought of losing you actually _did_ matter to him. His magic was leaving your body, because he was clearly to unstable to control it at the moment. You let out a defeated sigh and cover your face.

 

He moved to your face and took your hands away. He left gentle kisses everywhere, going from your forehead, to your cheeks, and finally he kissed your lips. And you kissed him back, because you were weak and you needed him just as much as he needed you.

 

His hands were trailing your body, his familiar touch lingering everywhere. He snuck his hand underneath your shirt and squeezed your sides. You giggled a little, and he loved how ticklish you were. 

 

…

 

Before you knew it, you were naked underneath him and he was kissing everywhere on your body. He sucked and nipped at your neck, and played with your breasts as he did so. You were letting out high pitched whimpers and he loved every second. You knew you shouldn’t be here, you knew you should’ve left but you just couldn't. He was all you had. Papyrus and him were your only family.

 

He swiftly removed his own pants and you whimpered as you saw he was already fully erect. You weren’t getting out of this.

 

“I love you.” He said against your forehead as he slid into you gently. You whimpered and moaned softly, clinging to his jacket. He felt so good, but you knew this was so wrong.

 

“No you don't.” you say back weakly. He holds your face and forces you to look at him.

 

“I love you so fucking much. Don’t fucking question it because you’re all I fucking want. Yeah, I fucked up. I fucked up and I will regret it for the rest of my life. But you're gonna be there with me.” His voice was stern but loving and you felt suddenly so warm but still so weak. 

 

You wrap your arms around his neck as he gently thrusts into you, sending waves of magic across your body.

 

You whine as he starts to speed up, increasing the pleasure for the both of you. You can feel the affection pulsing from his soul and you feel so good. You were close, and he knew because he started to rub small circles into your clit with one finger. You cry out in bliss, the feeling starting to overwhelm you.

 

You came and you were loud. You cried out his name and he laughed. He removed his fingers from your clit, letting you relax as he finished himself.

 

When he climaxed, he bit your shoulder, leaving another claim mark on your body. It stung with pleasure and you whined as he pulled out.

 

“I love you.” You choke out, weakly. And it was true.

 

“I love you too, babydoll.” He kissed your forehead and rolled over next to you, pulling you into his chest.

 

You just couldn’t leave him. 

 


	2. No mercy.

**Summary for the Chapter:**

> Alternative ending where reader leaves his cheating ass.
> 
> Same story, different ending.

**Notes for the Chapter:**

> FUCK YOU SANS.
> 
> The readers kinda heartless in this ending.
> 
> I would be too.

Standing outside of your shared bedroom door, you hear moaning and grunting coming from the inside.

 

This wouldn’t be unusual if you had only heard Sans, but you also heard a more feminine voice. 

 

 …

 

 _Fuck. No._ This was **_NOT_** happening. 

 

…

 

You open the door swiftly and watch as your boyfriend quickly untangles himself from some skanky looking girl that you’d never seen before. He stared at you for a few seconds, disbelief on his face.

 

“Princess, I-“ he starts, but you cut him off with a dismissive wave of your hand.

 

“Get out.” You say to the girl, your voice stern but wavering slightly. Thankfully, she didn’t argue. She quickly got up and put her clothes back on, and before she passed you she said “I-I’m so sorry. I didn’t know.” With a look of pity in her eyes, and she left quickly.

 

“Kitten…”

 

 

You look over at Sans, he was staring at you with a stern expression. You didn’t say anything, you just walked over to the closet and pulled out a bag. 

 

You start to stuff your clothes into it, carelessly as you wanted to get out of there before you started to cry.

 

“Oh, fucking hell.” You hear him quietly murmur.

 

He stood up and pulled his pants back on “Stop it, you aint leaving me.” He said as he grabbed your arm, but you quickly snatched it away.

 

“Don't _fucking_ touch me!” you shout at him, the tears you were holding back finally coming out. “Oh fuck,” he said softly under his breathe, and his eyes went soft. “Don't cry, no, no, no please don’t.” he held your face in his hands and you let the tears fall freely. You pulled yourself away from his gentle touch reluctantly, and made your way over to the dresser, shoving more miscellaneous items into your bag. 

 

“Stop!” he commanded once again, grabbing your bag and pulling it away from you successfully.

 

“Sans I swear to god, if you do not give me my bag back this instant I will **_scream_**!” you exclaim, grabbing for it again. He sighs softly. “Look, it didn’t mean anything. You don’t have to leave.” His voice was stern and it made you even more angry.

 

“ARE YOU FUCKING KIDDING ME!? YOU SLEPT WITH THAT GIRL IN OUR BED AND CLAIM IT DOESN’T MEAN ANYTHING!?” you scream at him, pushing him in the process. He growls at you and you manage to take your bag away from him. You start to leave the room and he grabs your hand.

 

“ _Fuck off_!” you scream. You were practically seeing red and you needed to get the hell out of there. You could go to the Inn. You had enough money saved up to go there for a while.

 

You exit the room and start to go down the stairs when he teleported in front of you, pulling you against him. “Stop.” He says again, and you fucking slap him.

 

You pull back, shocked that you actually just did that. He looked shocked and hurt. You almost felt bad for him. Almost. 

 

“WHAT IS GOING ON IN HERE?” Papyrus asks you both, emerging from the kitchen.

 

“Your brothers a cheating slut. But I guess that fine because it didn’t mean anything.” You say, not missing a beat. Sans looked so broken, but you didn’t care. You were so hurt. You gave this asshole _everything_ you had.

 

“OH. OH UM. OH MY. OKAY IM… I’M GONNA FINISH MAKING DINNER? OR… ARE YOU LEAVING US, HUMAN?” Papyrus asks you softly, nervous for the ending. Papyrus was your best friend, even if he was intimidating as all hell. You felt bad that you wouldn’t be roommates anymore. 

 

“Yeah. I’m sorry Papyrus. I can’t stay.” Your voice breaks a little and he looks upset. Sans was still staring at you, a broken look on his face. It broke your heart, but it was already broken so what the hell. 

 

“Please don’t go.” Sans manages to say, grabbing your hand again, gently. 

 

“I have to. You broke my fucking heart, _asshole_. Bye Papyrus.” You say softly and you exit the door.

 

…

 

Sans sits down on the steps with a pained expression on his face and winces. 

 

“WELL, IT SEEMS YOU HAVE ROYALY FUCKED UP BROTHER.” Papyrus says before going back into the kitchen, leaving him to suffer in silence. 

 

 

 

…fuck. You really left him.

 

 

**Notes for the Chapter:**

> Poor sans. 
> 
>  
> 
> ...
> 
>  
> 
> That moment when you contradict yourself.


	3. Forgiveness

**Summary for the Chapter:**

> Third alternative ending.
> 
> This one's my favorite.
> 
> FORGIVENESS AND REVENGE AND FLUFF.

**Notes for the Chapter:**

> Same story. Different ending. Kinda wanna make a one shot about the week. Should I? Hmmm.

Standing outside of your shared bedroom door, you hear moaning and grunting coming from the inside.

 

This wouldn’t be unusual if you had only heard Sans, but you also heard a more feminine voice. 

 

 …

 

 _Fuck. No._ This was **_NOT_** happening. 

 

…

 

You open the door swiftly and watch as your boyfriend quickly untangles himself from some skanky looking girl that you’d never seen before. He stared at you for a few seconds, disbelief and fear on his face.

 

“Princess, wait, I-“ he starts, but you cut him off with a dismissive wave of your hand.

 

“Get out.” You say to the girl, your voice stern but wavering slightly. Thankfully, she didn’t argue. She quickly got up and put her clothes back on, and before she passed you she said “I-I’m so sorry. I didn’t know.” With a look of pity in her eyes, and she left quickly.

 

“Kitten…”

 

 

You look over at Sans, he was staring at you with a worried expression. You didn’t say anything, you just walked over to the closet and pulled out a bag. 

 

You start to stuff your clothes into it, carelessly as you wanted to get out of there before you started to cry.

 

“Oh, shit. No.” You hear him quietly murmur.

 

He got up and put his pants on, before walking over to you and saying “Wait baby girl, please, let’s talk before you do anything you'll regret.” You whip around and look at him with pain in your face.

 

“You fucking cheated on me.  Why the fuck would I regret this?” you challenge, pushing him softly. He glared at you and said “Because I fucking love you!” he shouts at you and your taken aback.

 

Oh.

 

You felt your heart sting when he said those words, because you _knew_ they were true. 

 

Oh fucking well. He didn’t deserve you! Cheating _fuck_.

 

“You're _not_ leaving. We need to talk about this.” His voice was stern and it made you angry.

 

He went and stood in front of the door, locking it and staring at you longingly. Like he wanted to _touch_ you. Asshole.

 

“ ** _Move_**.” You try to say it sternly, but your voice was so small. He rolled his eyes and refused to move.

 

“I’m sorry.” He says softly and you all but snarl at him. His eyes went soft and you felt weak in your knees.

 

“Okay. I’ll bite. Why?” you ask him, crossing your arms and staring into his eyes. 

 

“Huh?” he asked, sounding genuinely confused. You gave him a nasty glare. “Oh! Oh, right.” He started, and you sighed, moving to sit on the bed while you listened to his dumb excuses.

 

“This is going to sound selfish and stupid, but I really needed to know.” He starts, taking a breathe. “I wanted to see if any other human could make me feel the way you do, or if I was really fucking bound to you. I wanted to know if it was a human thing, or a _you thing_. I know, I know I’m fucking dumb… but she was nothing like you. She was trash compared to you _, and oh my god, I can’t believe I hurt you._ Fuck, I didn’t mean to baby girl, I _promise_ I didn’t mean to. And I seriously, from the bottom of my soul, I am so, _so fucking sorry_.” His voice was breaking and you felt the pain in his voice.

 

You let out a shaky breath. It… it kind of made sense. Right? Fuck. 

 

“You… you betrayed me. I really don’t think I can stay now.” You say, voice wavering.

 

“No, please, _please_. Baby girl, I’ll do **_ANYTHING_**. Name it. _Anything_. Please, just don't leave me. _Please_.” He had gotten on his knees in front of you, holding your hands as you sat on the bed.

 

“I don’t think there’s anything you _can_ do.” You say sadly. He broke your trust.

 

He whined softly, and laid his head in your lap. You wanted to smack the _shit_ out of him, but you didn't. You couldn’t. He was just as broken as you were. He had the worst childhood…

 

Why the **_FUCK_** were you defending his cheating ass!?

 

…oh right, because you love him. ~~Shit~~.

 

He started to fucking cry into your lap and you felt so conflicted.

 

“Stop, you have **_no_** right to cry right now.” You say, your voice starting to break as well.

 

“I’m scared, okay!?” he admits softly, turning his head to look up at you.

 

“Scared of what!?” you ask.

 

“I’m scared that I’m gonna lose you.” He says, but it’s muffled because he hid his face in your lap again.

 

You felt your heart skip a beat and you wanted to scream. He couldn’t do this and be off Scott free. 

 

...

 

 

“Fucking hell. I’m not leaving…” you finally say, but you're hesitant. “But,” you start, and he looks up at you. “You're not touching me for a fucking week.” 

 

He looked so shocked and upset it was almost funny. “You're fucking joking, right!?” he asked desperately. You usually had sex at least once every 2 days because he was so fucking territorial, but he didn’t deserve you. Not right now at least.

 

“I’m being serious.” You say sternly. He fucking whines and falls to the floor like a 3 year old and you roll your eyes. Fucking dramatic much?

 

“But I **_need_** you!” he cries out, and you almost laugh. He looks so childish. 

 

 _“No.”_ you say sternly.

 

This week was gonna be _fun._

 

**Notes for the Chapter:**

> Thank you all for reading :) and for your nice comments.

**Author's Note:**

> Yeah tell me how you feel. And please let me know of any errors. Thank you!~~


End file.
